REVIEW OF REASEARCH PROCESS AND APPLICATION OF ULTRASONIC TESTING FOR ROCK AND SOIL

When the ultrasonic wave propagates in rock and soil, it carries lots of information related to the physical and mechanical properties of geotechnical medium. The information can be integrated and reflected in change of a series of acoustic parameters including ultrasonic velocity, attenuation coefficient, waveform, frequency, frequency spectrum and amplitude. Based on these parameters, the physical and mechanical properties of rock mass and mesoscopic structure characteristics can be investigated indirectly, so as to solve a series of geotechnical engineering problems. In this paper, the geotechnical problems which can be resolved by ultrasonic nondestructive testing are summarized. A systematic review is performed on the progresses of ultrasonic testing in soil and rock, which include the work of soil strength parameters, the microstructure of soil parameters, the obtaining of rock strength parameters by ultrasonic test, the rock fracturing mechanism, the application of ultrasonic wave attenuation in rock materials, the anisotropy of ultrasonic velocity and attenuation and research of ultrasonic test in flow test. Finally, the ultrasonic test is broadened in the research field of rock and soil aggregate. Wave velocity and attenuation law with specimens of different rock percentage are discussed. Also during compressive test, the meso-damage characteristics are analyzed with acoustic parameters, to illustrate that the rock and soil aggregate which is not only different from soil but also different from rock. Based on the above research, the development tendency of ultrasonic test is also prospected.